Manufacturing an electronic device, such as a semiconductor die having integrated circuitry, can include testing the electronic device, which can be termed a device under test or “DUT.” (As used herein, a DUT can be, by way of example and not limitation, any of the following: semiconductor dies unsingulated from a semiconductor wafer, singulated unpackaged semiconductor dies, singulated packaged semiconductor dies, an array or other arrangement of semiconductor dies (packaged or unpackaged) disposed in a carrier or other holding device, multi-die electronics modules, printed circuit boards, or the like, or combinations of the foregoing.) A typical testing system can include a tester and a probe card assembly. The probe card assembly can provide a physical interface to the DUTs by providing pressure contacts between probes of the probe card assembly and test points on the DUTs. The tester can control testing of the DUTs, for example, controlling the generation of stimulus signals applied to the DUTs and monitoring response signals produced by the DUTs. The signals can be provided to the DUTs through communications channels between the tester and the probe card assembly. Each channel can include circuitry configured to generate and/or drive a test signal to be input to a test point on a DUT and/or to monitor at that or another test point on the DUT an output signal produced by the DUT in response to the test signal. Each channel can be an AC channel or a DC channel.
It can be beneficial to test a number of DUTs in parallel. For example, parallel testing can provide higher throughput in the production process and/or test apparatus utilization. The trend to test increasing numbers of DUTs in parallel has resulted in ever increasing demands on the number of channels provided by a test system. In some cases, these demands have outpaced the growth in tester capacity. Moreover, providing an increase in the number of channels in a test system can be a significant cost factor.
Sharing of AC channels (see definition of AC channel below) has been implemented in some test systems by providing for fan out in the probe card assembly to distribute an AC test signal driven from an AC test resource in the tester to multiple DUTs. Unfortunately, these fan out schemes cannot be readily applied to share DC channels (see definition of DC channel below). Some embodiments of the present invention address utilizing one DC channel to provide test signals to and/or sense test signals from more than one test point on a DUT and/or more than one DUT.